Hi, Ramon I have a strong opinion, based on testing of various smocks and smock grounding methods I performed when I was an ESD site coordinator for an EMS provider. First, I tested the smocks by themselves using the methods in EOS/ESD 20.20-1999, in the "how-to document". This can be downloaded from the EOS/ESD website http://www.esda.org/freedowloads.html. I also tested several different vendor's smocks while they were worn by various operators, using a field meter to measure the charge buildup from different activities, including simply walking. When testing smocks without elastic cuffs, a significant (>1000V) triboelectric charge can easily be generated into the smock by a sweater, the hood of a sweatshirt, or simply from hair contacting the smock around the collar or shoulders, or just by walking. Because this type of smock does not make contact with the skin of the wearer, this triboelectric charge had no place to drain until it came in contact with ground, which was often through the ESD-sensitive component or assembly. In fact, it was found that unless the smock was grounded to the operator's skin via a dissipative cuff or by grounding the smock ground snap to the electrical ground connection used for the wriststrap, it was actually better to not wear a smock at all in most cases. If the operator is wearing ESD shoes or heel straps the charges built up on the cuffed smock are dissipated through the wearer's body and into the ESD flooring, or at least through the wrist strap when it is plugged in. Even if ESD flooring is not used, bare concrete does have dissipative properties. So if you are evaluating smocks, I would specify one with elastic dissipative cuffs. Some operators do not like them at first, but after they wore them awhile they actually liked them better because their sleeves never snagged on assemblies or other hardware, pulling them off the bench or shelf or tote onto the floor. The other alternative is to ground the smocks when seated or when standing and handling ESD devices directly with a second ground cord. However, this is a royal annoyance. Another method is to have a short ground strap that goes from the snap on the end of the sleeve to a second snap on the wrist strap. However, this little loop of wire often snags. But whatever you do, make sure you pay three times the price of a regular smock by getting the green ones that are "RoHS-Compliant". LOL ;o) -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Dehoyos, Ramon Sent: Thursday, February 01, 2007 9:27 AM To: [log in to unmask] Subject: [TN] FW: January 2007 ESD Systems.com Newsletter Technetters: Does any body have an opinion on grounded Smocks? Ramon ________________________________ From: [log in to unmask] [mailto:[log in to unmask]] On Behalf Of Banana Jack Sent: Tuesday, January 23, 2007 2:30 AM To: Lusby, Jack R. Subject: January 2007 ESD Systems.com Newsletter Here is the latest ESD news from ESD Systems.com: http://www.ESDSystems.com/Newsletters/v10issue1.html --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------